"I have not made a decision," the president said in an interview with the PBS NewsHour at the White House, reiterating he is weighing options in the wake of the chemical attack in the suburbs of Damascus, capital of Syria, Aug 21, in which 1,300 people were reportedly killed, Xinhua reported.
But he said the international norm against the use of banned weapons needs to be "kept in place".
"We have concluded that the Syrian government in fact carried these out, and if that's so, then there need to be international consequences," he added. "I have no interest in any kind of open- ended conflict in Syria."
US House of Representatives Speaker John Boehner Wednesday joined some of his peers by sending a letter to Obama, calling on the president to make his case for launching military strikes on Syria in response to the gas attack.
The top lawmaker demanded that Obama "make the case to the American people and Congress for how potential military action will secure American national security interests, preserve America's credibility, deter the future use of chemical weapons, and, critically, be a part of our broader policy and strategy".
"I think it's important that if, we make a choice to have repercussions for the use of chemical weapons, then the (Bashar al-Assad) Assad regime, which is involved in a civil war, trying to protect itself, will have received a pretty strong signal, that in fact, it better not do it again," Obama said.
Obama pledged a "limited, tailored approach" that will not draw the United States into the conflict, saying direct military engagement "would not help the situation on the ground."
US media reported that the military strikes under consideration will hit targets inside Syria, involving sea-launched cruise missiles or possibly long-range bombers.
Administration officials said the options aim not at toppling the Syrian government led by al-Assad, but rather a direct response to the use of sarin gas last week.
The Syrian government and opposition, engaged in conflict since March 2011, have been blaming each other for the alleged use of the chemical weapons.
An assessment on Syrian government's culpability is expected to be released by the American intelligence later this week.